The present invention relates to boats having inboard motors. More particularly, the present invention relates to a steering mechanism for high speed boats. With still more particularity, the present invention relates to a steering mechanism for a boat having dual drive shaft in which the props, driven by inboard motors through the drive shafts, are maintained at an essentially constant depth whether the boat is being driven staright or is heeling in a turn.
Historically, high speed motor boats having dual drive shafts and dual props are such that they tend to lose speed and skid in high speed turns. Such loss of speed and skidding occurs because previous steering arrangements have typically failed to adequately compensate for the driving of the prop on the inboard side of a turn deeper into the water and the raising of the prop on the outboard side of the turn up and sometimes out of the water as the boat heels in a turn.
Such loss of control and speed is critical and can be dangerous in situations such as races where boats operate at tremendous speeds and closed aboard one another. Steering problems are capable of being solved by steering systems which compensate for heel although no system is known which has thus far solved the problem in its entirety.
One arrangement which to some extent goes to the solution of such steering related problems can be found in U.S. Pats. Nos. 4,544,362 and 4,645,463 to Arneson. In particular, Drawing FIGS. 11 and 12 of the Arneson patents, the latter of which is a continuation of the former, together with the explanation of those figures will provide an appreciation that both of the props in the Arneson system move vertically upward or downward, as the steering mechanism is actuated, in a manner such that the relative movement of the two props in both the vertical and horizontal directions is identical.
The props move along discrete arcs defined one per each prop because each drive shaft is supported independently, at separate points on the transom, which are vertically directly above the point of connection of the respective propeller shaft carriers 30' to the transom. Therefore, as the boat is turned, the props each concurrently move vertically upward or downward along two horizontally separate arcs centered on steering axes S'-S'. See specifically column 6, lines 33-68, and column 7, lines 1-6, in the latter Arneson patent. FIG. 9 in the Arneson patents will likewise be useful in understanding the Arneson system.
While the Arneson system addresses the problems indentified above to an extent, the need continues to exist for a steering mechanism for high speed, high power, dual prop boats which to a more agressive degree compensates for the tendency of one prop to "dig in" to the water and for the opposite prop to raise out of the water as the boat heels in a turn.